1. Field of the Invention
The present invention relates to computer systems that incorporate array controllers and storage subsystems. More particularly, the present invention relates to array controllers adapted to allow rearrangement and automatic reconfiguration of hard disk drives within a storage subsystem without storage loss. The rearrangement of hard disk drives includes, but is not limited to, the rearrangement of hard drives within a storage subsystem and/or the addition of one or more logical drive units into a storage subsystem.
2. Description of the Related Art
A drive array is simply a collection of hard disk drives or physical drives which are grouped together to create an array of physical drives. An array is made up of one or more subsets called logical drives (sometimes called logical volumes) which are spread across one or more physical drives in the array. Operating systems view logical drives as a single, contiguous storage space although it may be made up of several physical drives.
A generic drive array contained in a storage subsystem is illustrated in FIG. 1 and consists of one logical unit spread across three physical drives. FIGS. 2 and 3 illustrate other drive array configurations found within a storage subsystem. In particular, FIG. 2 illustrates a storage subsystem having six physical drives that are configured to be one drive array having two logical drives. FIG. 3 illustrates a storage subsystem consisting of one drive array consisting of three physical drives wherein there are two logical drives spread across the three physical drives. One of ordinary skill in the art will understand that there are many ways to configure one or more drive arrays found within a storage subsystem or subsystems.